JP3986356B2 - Electric double layer capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a high-quality electric double-layer capacitor where a sub stance interposed between a container and a capacitor body is not carbonized in the electric double-layer capacitor provided with the capacitor body made by rolling a belt-shaped positive electrode and a belt-shaped negative electrode and a separator which separates the two electrodes and a container which seals the capacitor body together with the electrolytic solution. <P>SOLUTION: A winding of the belt-shaped negative electrode 11b is set to be longer by one final turn the that of the belt-shaped positive electrode 11a. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric double layer capacitor.
[0002]
[Prior art]
2. Description of the Related Art In recent years, attention has been focused on electric double layer capacitor application technologies that can be rapidly charged and have a long charge / discharge cycle life as various power storage devices.
[0003]
FIG. 6 is a schematic view illustrating the configuration of the electric double layer capacitor, in which the positive electrode body 1a, the negative electrode body 1b, and the separator 2 are alternately stacked. The multilayer body 3 (capacitor body) is immersed in an electrolytic solution, accommodated in a container (not shown), and sealed.
[0004]
The positive electrode body 1a and the negative electrode body 1b are composed of activated carbon electrodes 4a and 4b (polarizable electrodes) and collector electrodes 5a and 5b (aluminum electrodes). Electric charges are accumulated in the activated carbon electrodes 4a and 4b, and electricity is taken in and out of the collector electrode 5a. , 5b. Since the number of the positive electrode bodies 1a and the number of the negative electrode bodies 1b is the same, in the laminated body 3, when one end is the positive electrode body 1a, the other end is the negative electrode body 1b.
[0005]
In JP-A-2001-52974, a capacitor body configured in a roll form from a strip-shaped positive electrode body and a strip-shaped negative electrode body and a separator separating them, a container for sealing the capacitor body together with an electrolyte, What comprises is disclosed.
[0006]
[Problems to be solved by the invention]
With regard to such an electric double layer capacitor, various kinds of research and development are accumulated, and a substance composed of carbon, hydrogen, oxygen, etc. in contact with the surface of the positive electrode between the laminate and the container (for example, paper such as cellulose) ), The substance was dehydrated and carbonized.
[0007]
In the case of FIG. 6, the paper separator (outermost layer of the laminate 3) interposed between the positive electrode body 1a at the right end and the container is carbonized. Carbide is easily broken finely, and if this floats the electrolyte, leakage current is likely to occur, and the self-discharge characteristics may be deteriorated.
[0008]
The present invention has been made based on such knowledge, and aims to realize a high-quality electric double layer capacitor that does not cause carbonization of a substance between the container and the capacitor body.
[0009]
[Means for Solving the Problems]
1st invention is comprised by the roll winding from the strip | belt-shaped positive electrode body which consists of a collector electrode and an activated carbon electrode, the strip | belt-shaped negative electrode body which consists of a collector electrode, and an activated carbon electrode, and the separator which consists of a porous membrane which separates these. And a container for sealing the capacitor body together with the electrolyte, in which the strip-shaped negative electrode body is disposed inside the positive electrode body to form a roll-shaped wound body, and the strip-shaped negative electrode The body is characterized in that the end side of the roll winding is set longer than one winding than the belt-like positive electrode body.
[0010]
The second invention is characterized in that a separator for separating the strip-shaped positive electrode body and the strip-shaped negative electrode body is set long for one turn together with the strip-shaped negative electrode body .
[0012]
【The invention's effect】
In the first invention, a strip-shaped body (corresponding to the material of the capacitor body) is formed by overlapping the strip-shaped positive electrode body, the strip-shaped negative electrode body, and the separator separating them. The capacitor body is configured as a roll-shaped wound body.
[0013]
The cross section of the roll winding becomes a positive electrode and a negative polar body separator degree overlapping alternately squeezing all husk, radially, at the end side of the roll winding, the negative electrode body of at least one turn of a long setting, until then It is wound around a separator that is the outermost layer to form the outermost layer of the capacitor body. Therefore, since the positive electrode body does not become the outermost layer of the capacitor body, even if there is a substance composed of carbon, hydrogen, oxygen, etc. (for example, paper such as cellulose) in contact with the surface of the outermost layer, the substance is dehydrated. There is no such thing as carbonization.
[0014]
About the separator which separates between a negative electrode body and a positive electrode body, setting with long with a negative electrode body is also considered. Even in that case, the separator that is the outermost layer of the wound body is a negative electrode body that is set longer than one turn, and the positive electrode body does not contact the separator of the outermost layer. However, this does not cause dehydration and carbonization.
[0015]
As a result, it is possible to inexpensively provide a high-quality electric double layer capacitor that avoids carbonization of a material such as paper and has good self-discharge characteristics between the container and the capacitor body.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
An example of the electric double layer capacitor according to the first embodiment will be described with reference to FIGS. 1 to 3. A roll is formed from a strip-shaped positive electrode body 11 a, a strip-shaped negative electrode body 11 b, and separators 12 a and 12 b that separate them. The capacitor main body 13 comprised in a winding, and the container 20 which seals the capacitor main body 13 with electrolyte solution are provided.
[0019]
The container 20 is formed into a bottomed cylindrical shape from a lightweight metal (for example, aluminum). Reference numeral 20a denotes a metal (for example, aluminum) lid that seals the opening of the container 20, and the inner surface of the container 20 and the inner surface of the lid 20a are covered with an insulating layer. Reference numerals 21a and 21b denote a pair of terminals, each of which includes a conductive portion 22 that penetrates the lid 20a and an insulating portion 23 that is interposed between the lid 20a and the conductive portion 22.
[0020]
In FIG. 3, the positive electrode body 11a and the negative electrode body 11b are composed of collector electrodes 15a and 15b and activated carbon electrodes 16a and 16b (polarizable electrodes). These collector electrodes 15a and 15b are made of strip-shaped metal foil (for example, aluminum foil), and activated carbon electrodes 16a and 16b are formed on both surfaces thereof. A strip-shaped positive electrode body 11a is stacked on the strip-shaped plane of the negative electrode body 11b via a separator 12b (a porous film made of paper or the like), and the separator 12a is stacked on the strip-shaped plane of the positive electrode body 11a. (Material of the capacitor body 13) is formed.
[0021]
As shown in FIG. 2, the belt-like body 17 is formed on the roll-shaped wound body 13 (capacitor body) by rolling the negative electrode body 11b inward. In order to make the outermost layer of the wound body 13 into a negative electrode, the strip-shaped negative electrode body 11b is set longer by one turn on the end side of the roll winding than the strip-shaped positive electrode body 11a.
[0022]
The cross section of the wound body 17 is such that the positive electrode body 11a and the negative electrode body 11b are alternately overlapped in the radial direction while sandwiching the separators 12a and 12b, and the negative electrode body in which one winding is set longer at the end side of the roll winding 11b is wound around the outermost layer (separator 12a) so far, and forms the outermost layer of the wound body 13.
[0023]
The capacitor body 13 is immersed in the electrolytic solution and accommodated in the container 20. Polarity corresponding terminals 21a and 21b are connected to the collector electrodes 16a and 16b of the positive electrode body 11a and the negative electrode body 11b, respectively, and the container 20 is sealed with a lid 20a.
[0024]
With such a configuration, the outermost layer of the wound body 13 becomes the negative electrode body 11b, and the polarity of the outermost layer does not become the positive electrode. Therefore, a substance (paper or the like) composed of carbon, hydrogen, oxygen, etc. in contact with the surface of the outermost layer ) Does not cause dehydration and carbonization of the substance.
[0025]
In order to protect the electrode surface of the negative electrode body 11b, the separator 12b that separates the positive electrode body 11a and the negative electrode body 11b may be set longer by one turn together with the negative electrode body 11b. In that case, the outermost layer of the wound body 13 is the separator 12b, but the separator 12b is in contact with the negative electrode body 11b with one winding set longer, and the positive electrode body 11a is not in contact with the outermost layer separator 12b. Even if the separator 12b is made of paper, it does not dehydrate and carbonize.
[0026]
As a result, it is possible to inexpensively provide a high-quality electric double layer capacitor that can avoid carbonization of a substance such as paper and has good self-discharge characteristics between the container 20 and the capacitor body 13.
[0027]
The electric double layer capacitor according to the reference example will be described with reference to FIGS. 1, 3, and 4. A cylindrical negative electrode body 18 that surrounds the outer periphery of the capacitor body 13a is provided. The capacitor body 13a is formed into a roll-type wound body by rolling the negative electrode body 11b inward from the four-layer belt-like body 17A. In the four-layer strip 17A, the lengths of the positive electrode 11a and the negative electrode 11b (and the separators 12a and 12b) are set to be the same.
[0028]
The capacitor main body 13a is housed in a cylindrical negative electrode body 18, and the whole is immersed in an electrolytic solution and accommodated in a container. The cylindrical negative electrode body 18 may be a simple conductive material cylinder (for example, aluminum), or may have an activated carbon electrode on both sides of a collector electrode (for example, aluminum foil). It is connected to the negative terminal 21b. The capacitor body 13a is connected to the collector electrodes 16a and 16b of the positive electrode body 11a and the negative electrode body 11b with the corresponding terminals 21a and 21b, and the container 20 is sealed with a lid 20a.
[0029]
With such a configuration, even if there is a substance composed of carbon, hydrogen, oxygen, etc. between the cylindrical negative electrode body 18 and the container 20, the substance is in contact with the cylindrical negative electrode body 18, Since it does not contact the surface of the positive electrode, the occurrence of carbonization is avoided and the self-discharge characteristics of the electric double layer capacitor can be maintained well.
[0030]
In order to save material costs, the activated carbon electrode is formed not only on both sides of the collector electrode but on the inner surface of the cylinder for the cylindrical negative electrode body 18 (the activated carbon electrode is omitted on the outer surface of the cylinder). May be.
[0031]
A reference example will be described with reference to FIGS. 1 and 5. The capacitor body 13 b is formed into a roll-shaped wound body by rolling the positive electrode body 11 a inward from the four-layer belt-like body 17 B.
[0032]
In the four-layer belt-like body 17B, the belt-like negative electrode body 11b is overlaid on the belt-like plane of the positive electrode body 11a via a separator 12a (a porous film made of paper or the like), and the separator 12b is overlaid on the belt-like plane of the negative electrode body 11b. Thus, the positive electrode body 11a and the negative electrode body 11b (and the separators 12a and 12b) are set to the same length.
[0033]
The capacitor body 13 is immersed in the electrolytic solution and accommodated in the container 20. Polarity corresponding terminals 21a and 21b are connected to the collector electrodes 16a and 16b of the positive electrode body 11a and the negative electrode body 11b, respectively, and the container 20 is sealed with a lid 20a.
[0034]
With such a configuration, the outermost layer of the wound body 13b becomes the separator 12b, and the separator 12b is in contact with the negative electrode body 11b. Since the positive electrode body 11a does not contact the outermost layer separator 12b, the separator 12b is made of paper. Even so, dehydration does not occur and carbonization does not occur.
[0035]
As a result, it is possible to inexpensively provide a high-quality electric double layer capacitor that can avoid carbonization of a substance such as paper and has good self-discharge characteristics between the container 20 and the capacitor body 13b.
[Brief description of the drawings]
FIG. 1 is an external view of an electric double layer capacitor according to the present invention.
FIG. 2 is a perspective view illustrating the configuration of the capacitor body.
FIG. 3 is a cross-sectional view for explaining the material of the capacitor main body.
FIG. 4 is a perspective view illustrating a reference example .
FIG. 5 is a perspective view illustrating a reference example . FIG. 6 is a schematic diagram illustrating a configuration of an electric double layer according to a conventional technique.
[Explanation of symbols]
11a Positive electrode body 11b Negative electrode body 12a, 12b Separator 13, 13a, 13b Capacitor body 15a, 15b Activated carbon electrode (polarizable electrode)
16a, 16b collector electrodes 17, 17A, 17B strips

Claims (2)

Capacitor body configured in roll form from a strip-shaped positive electrode body made of a collector electrode and an activated carbon electrode, a strip-shaped negative electrode body made of a collector electrode and an activated carbon electrode, and a separator made of a porous film separating them, and a capacitor And a container for sealing the main body together with an electrolyte solution. A strip-shaped negative electrode body is disposed inside the positive electrode body to form a roll-shaped wound body, and the strip-shaped negative electrode body is a strip-shaped positive electrode body. An electric double layer capacitor characterized in that the end side of the roll winding is set longer than one winding. 2. The electric double layer capacitor according to claim 1, wherein the separator separating the strip-shaped positive electrode body and the strip-shaped negative electrode body is set to be longer by one turn together with the strip-shaped negative electrode body.

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